1. Field of the Invention
The present invention relates to a fuel flow rate measuring apparatus for an internal combustion engine of a vehicle, a ship or the like, and in particular, to a technique to achieve cost reduction as well as to improve reliability.
2. Description of the Related Art
In known fuel flow rate measuring apparatuses for internal combustion engines, injection pulse widths (the number of drivings or drive frequency of injectors) are detected and added up or integrated, and an amount of fuel injected within an appropriate period of time (the flow rate of fuel per unit time) is calculated from a predetermined constant (unique fuel injection amount characteristic constant) (for instance, see a first patent document: Japanese patent application laid-open No. H6-278505).
In addition, in known fuel flow rate measuring apparatuses for marine internal combustion engines, fuel piping dedicated for measurements of the flow rate of fuel is arranged to extend from internal combustion engine fuel piping at the back side of the hull of a ship up to a fuel flow meter on an instrument panel of a cockpit at the front side of the hull.
In the known fuel flow rate measuring apparatuses for internal combustion engines, only a single parameter (constant) matched for the normally used range is provided for the fuel injection amount characteristic per drive time of each injector, which is not necessarily a linear characteristic over the entire flow rate range. As a result, there is the following problem, for example. That is, there arises a mismatch for the fuel injection amount characteristic at low flow rates (when the width of an injection pulse is short), so errors might occur in the flow rate of fuel measured at the time of low flow rates.
In addition, the existence of piping dedicated for use with the fuel flow rate measuring apparatus results in the following problems. That is, installation man-hours and costs increase, and reliability is reduced due to bending of the piping, etc.